LOGIOR

When integers are viewed in their two's complement representation,
logior returns their bitwise logical inclusive or. In ACL2 logior is a
macro that expands into calls of the binary function binary-logior,
except that (logior) expands to 0 and (logior x) expands to x.

The guard for binary-logior requires its arguments to be integers.
Logior is defined in Common Lisp. See any Common Lisp
documentation for more information.